Reducing the processor operating time for a programmable controller

ABSTRACT

A programmable controller having a processing unit, a screen, a control panel, and signal inputs and outputs, all of which are accommodated in a common housing. Switching functions can be programmed by the user via a menu-driven user interface on the screen. The status display is capable of being switched between an active and an inactive display status of the screen.

FIELD OF THE INVENTION

The present invention relates to a programmable controller having aprocessing unit, a display screen, an operator unit and signal inputsand signal outputs, where the processing unit, the display screen, theoperator unit, the signal inputs and signal outputs are accommodated ina common housing, and where switching functions can be programmed by theuser on the basis of predetermined functions by using a menu-assisteduser interface on the display screen.

RELATED TECHNOLOGY

Such controllers have been programmed in a STOP state (applicationprogram not active) of the controller using a control panel integratedinto the controller, with graphical monitoring of a screen likewiseintegrated into the controller. Further, the application program can beexamined via the screen of the controller in the STOP state, and signalstates of inputs and outputs of the controller are graphically presentedin the RUN state (application program active).

SUMMARY OF THE INVENTION

An object of the present invention is to devise such a programmablecontroller, which markedly increases the capacity of the controllerwhile maintaining the same level of operator convenience or programmingconvenience.

The present invention provides a programmable controller having aprocessing unit, a screen (14), a control panel (8), and having signalinputs (4) and signal outputs (6), the processing unit, the screen (14),the control panel (8), the signal inputs (4) and signal outputs (6)being accommodated in a common housing (2), and switching functionsbeing programmable by the user via a menu-driven user interface on thescreen (14). The status display is capable of being switched between anactive display status, in which signal states of inputs and outputs ofthe controller, as well as signal states of function blocks and the likeare displayed on the screen, and an inactive display status, in which noinstantaneous display of signal states is presented on the screen.

According to the present invention, the processor running time or thecycle time of an executing (active) application program can beinfluenced in that the status display of the screen is capable of beingswitched between an active display status, in which signal states ofinputs and outputs of the controller, and signal states of functionblocks and the like, are displayed on the screen, and an inactivedisplay status, in which no current display of signal states ispresented on the screen. In standard mode, the status display on thescreen is active. For this purpose, the signal states to be displayedmust be interrogated at regular intervals during the execution of theapplication program and resupplied to the display (refresh). Thisrefresh, however, requires valuable cycle time. In accordance with thepresent invention, the controller design makes it possible to turn offthe screen's status display, so that there is no refresh at regularintervals, and the cycle time is correspondingly reduced. In this way,processes that are even more time-critical can advantageously bemanaged.

In a specific embodiment of the present invention, a combination of atleast two keys causes the status of the display status to be switched.Thus the status display is switched by preferably mutual actuation oftwo defined keys. In another specific embodiment of the presentinvention, this switching is implemented automatically, for example bythe status display being activated only in every n-th cycle. If theaverage cycle time is 5-10 ms and a characteristic time relating to theperceptual capacity of the human eye is approximately 200 ms, it isdesirable to activate the status display only in every twentieth tofortieth cycle, and thus to achieve a reduction of the cycle time.

DESCRIPTION OF THE DRAWINGS

Further advantages of the present invention are discussed in furtherdetail below with reference to the drawings, in which:

FIG. 1 shows a schematic diagram of a programmable logic controller.

FIG. 2 shows an application program in terms of cycle time in the formof a cycle timing diagram.

DETAILED DESCRIPTION

FIG. 1 shows a programmable logic controller having a housing 2, andhaving an array of signal inputs 4 and signal outputs 6. Monitored by aprogram (application program), the programmable logic controllerswitches the current flowing between the signal inputs 4 and the signaloutputs 6. The program can be input to the processing unit orprocessing/memory unit (e.g., microcontroller) of the controller via acontrol panel 8, which preferably includes four control keys 10 and amultifunction key 12. Input and program execution can be observed on ascreen 14. A menu-driven user interface is possible on screen 14 duringprogramming, while the status display of signal inputs and signaloutputs 4, 6 of the controller and/or the status display of signalinputs and signal outputs of function blocks and/or parameters offunction blocks is possible during operation. According to the presentinvention, the status display of screen 14 can be switched between anactive and an inactive status using predefined means 8, 10, 12. In onepreferred embodiment, switching is effected by the combination of twocontrol keys 10. It is also conceivable, however, to effect switching bya single key. Alternatively, the controller can also be programmed andthe parameters assigned from an external computer via interface 16.

FIG. 2 shows schematically an application program in terms of its cycletime (time for the one-time execution of the application program). Thecycle time is represented in the form of a cycle timing diagram. Theessential time segments of a cycle time are formed by “reading in ofsignal inputs” (I), “execution of application program,” “reading out tosignal outputs” (Q), an “operating system sector” (BTS), and at leastone “display sector” (A). If, through the design according to thepresent invention, the status display of screen 14 is switched into theinactive status, the portion of cycle time for the display sector (A)drops out, so that the cycle time is reduced by the time of the displaysector (A). In one further refinement of the present invention, thisstatus can be stored so that the previously set display status remainsset, even after a power outage with subsequent restarting of thecontroller. In the inactive display status, the screen display is notupdated (refreshed), and advantageously is simply turned off (nodisplay).

What is claimed is:
 1. A programmable controller comprising: aprocessing unit; a screen including a menu-driven user interface; acontrol panel; at least one signal input; at least one signal output;and a housing, the processing unit, the screen, the control panel, theat least one signal input and the at least one signal output beingdisposed in the housing; wherein a switching function of the controlleris arranged to switch the current flowing between the at least onesignal input and the at least one signal output and is programmableusing the menu-driven user interface, and wherein a status display ofthe screen is capable of being switched between an active display statusin which signal states of at least one of the signal input, the signaloutput and a function block of the programmable controller are displayedon the screen, and an inactive display status in which no currentdisplay of signal states is presented on the screen.
 2. The programmablecontroller as recited in claim 1 wherein the control panel includes akey useable for the switching of the status display.
 3. The programmablecontroller as recited in claim 1 wherein the control panel includes aplurality of keys, a combination of two or more of the keys beinguseable for the switching of the status display.
 4. The programmablecontroller as recited in claim 1 wherein a software is useable for theswitching of the status display.
 5. A programmable controller,comprising: a processing unit; a display screen; at least one signalinput; at least one signal output; a common housing, the processingunit, the display screen, the at least one signal input and the at leastone signal output accommodated in the common housing; and an arrangementconfigured to program switching functions to switch the current flowingbetween the at least one signal input and the at least one signal outputon the basis of predetermined function in accordance with amenu-assisted user interface on the display screen; wherein a statusdisplay of the screen is switchable between an active display status inwhich signal states of at least one of the at least one signal input,the at least one signal output and a function block of the programmablecontroller are displayed on the screen, and an inactive display statusin which no current display of signal states is presented on the screen.6. A programmable controller, comprising: processing means; displaymeans; at least one signal input; at least one signal output; a commonhousing, the processing means, the display means, the signal input andthe signal output accommodated in the common housing; and means forprogramming switching functions to switch the current flowing betweenthe at least one signal input and the at least one signal output on thebasis of predetermined functions in accordance with a menu-assisted userinterface on the display means; wherein a status display of the screenis switchable between an active display status in which signal states ofat least one of the at least one signal input, the at least one signaloutput and a function block of the programmable controller are displayedon the screen, and an inactive display status in which no currentdisplay of signal states is presented on the screen.